Ch.22 Respiratory physiology: the effects of anesthesia

1
Ch.22 Respiratory physiologythe effects of
anesthesia

• ??? 1?
• ???

2
Cellular respiration
1.Aerobic metabolism 2.Anaerobic metabolism

• ?? ?? ??? blood ? inspired air??? gas exchange?
  ?? ???, ??? cellular aerobic metabolism? ?? ? ??
  ????. ?, O2? ?? CO2? ??? ?? ???.
• 1. Aerobic Metabolism
• O2? ????, aerobical?? energy? ???.
• carbohydrates, and proteins? two-carbon fragments
  (acetyl CoA) ? ????.? CO2? ???? energy? ?? NAD,
  FAD, GTP? ????.? Oxidative phosphorylation ?
  ?? adenosine triphosphate(ATP) ? ??
• glucose  
• C6H12O6 6O2    ?  6CO2 6H2O energy
• energy ADP   P  ? ATP
• 38 ATP ??
• ?? ??? ?? ATP ?  ADP P energy
• Cell? ATP ADP  10 1 ? ????.
• ATP? ???? ?? ???, metabolic substrate? ?? ????
  ????? ???? ?

3
Cellular respiration
1.Aerobic metabolism 2.Anaerobic metabolism

• Respiratory quotient (RQ) total CO2
  production(VCO2)? oxygen consumption (VO2)?? ???,
  ???? ?? ??? primary type? ????.
• RQ of carbohydrates, lipid, protein 1.0, 0.7,
  0.8
• ????    VCO2 200mL/min  VO2 250mL/min?
• normal RQ  0.8 (????? protein? primary
  fuel source? ???? ????, fats and carbohydate
  combination??? ????.)
• VO2    10(weight)
• 2. Anaerobic Metabolism
• ??? ?? ATP??(2ATP)
• glucose? pyruvate, latic acid? ??? ?? ??
• 3.Effects of Anesthesia on Cell Metabolism
• ????? VO2? VCO2? ? ? 15?? ????
• ?? cerebral and cardiac oxygen consumption

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Functional respriatory anatomy
1.Rib musles 2.Trachea 3.Circulation 4.innervati
on

• 1. Rib Cage Muscles of Respiration
• contraction of the diaphragm
• the base of the thoracic cavity ? 1.5 -7cm ??
• chest volume ??? 75
• accessory respiration muscle? rib? ??? the
  chest? ?????.
• ?? ??? ?????? ? ?, SCM, scalene, pectoralis
  muscle? ??? ??.
• SCM rib cage?????? ??? ??.
• scalene ??? inward displacement of the upper
  rib? ????.
• pectoralis muscle chest expansion? ???.
• expiration is passive in supine position but
  becomes active in the upright position
• exhalation? abdominal muscles (rectus abdominis,
  external and internal oblique, transversus) ???
  internal intercostals ? ???? ??? ?? ????.
• some pharyngeal muscle airway patency ??? ??
• genioglossus, levator palati, tensor palati,
  palatopharyngeus, palatoglossus  

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Functional respriatory anatomy
1.Rib musles 2.Trachea 3.Circulation 4.innervati
on

• 2. Tracheobronchial Tree
• ? ??? ?? alveoli? gas flow? ??.
• ? ??? division?? trachea?? alveolar sacs?? 23
  division? ??.
• alveolar sac? 17 alveoli? ?? ? 300 milion
  alveoli? enormous membrane (50-100m2)? ????.
• Mucosa? ciliated columnar?? cuboidal?? gradual
  transition? ?? ????? alveolar epithelium? ??.
• gas exchange flat epithelium
• cartilagenous support? ??? smaller airways?
  patency? ?? ??? elastic recoil? radial traction?
  ???? ??.

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Functional respriatory anatomy
1.Rib musles 2.Trachea 3.Circulation 4.innervati
on

• Alveoli
• Alveolus ?? ??    0.05-0.33 mm
• in supine, largest alveolar apex  ,smallest
  base
• inspiration? alveolar size? ???? ????.
• ??? alveolus? wall? ?????? ???? ??.
• thin side (lt 0.4? ) gas exchange? ??, alveolar
  epithelium and capillary endothelium ? ?????.
• thick side (interstitial space)
• fluid and solute exchange ??
• alveolar epithelium? capillary endotheium ?
  ?????.
• pulmonary interstitial space ? ?? elastin,
  collagen, ??? ??? nerve fibers ? ????.
• 1-2?? alveolus? structural support ? ????.
• respiratory epithelium two cell type

1. type ?pneumocyte flat ?? tight junction ? ????
   albumin ?? oncotically  active molecules ?
   alveolus? ?????? ???? ??? ??.

• type ? pneumocyte round cell?? cytoplasmic
  inclusion(lamellar bodies)? ???? surfactant?? ???
  ????. ?? cell division ? ?? type?pneumocyte,
  alveolar macrophages, mast cells, lymphocytes,
  and APUD cell, Neutrophils? ????.

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Functional respriatory anatomy
1.Rib musles 2.Trachea 3.Circulation 4.innervati
on

• 3. Pulmonary Circulation Lymphatics
• two circulations, bronchial and pulmonary
• bronchial circulation
• the left heart?? ??
• trachoebronchial tree ???? ??? ?? ???
  respiratory bornchioles ?? metabolic needs?
  ??????.
• pulmonary circulation
• pulmonary artery? ???? right heart? total output
  ? ???.
• four main pulmonary veins? ?? left heart ? ????.
• bronchial ? pulmonary circulation ??? connection?
  ??. normal venous admixture? ?? ??? ???? ??
  ??? ?? ???? ?????.

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Functional respriatory anatomy

• Pulmonary Capillaries
• ????? ?? pressure ??? pulmonary circulation??
  capillary network? ?? ??? gravity? alveolar size
  ? ?? ?? ?? ???.
• pulmonary capillary endothelium? 5nm ?? ????? ?
  junction ? ??? ?? albumin?? ? molecules ? ???
  ????
• Macrophages? alveoli? ?? ?? ??? ?? bacterial
  infection? ???? foreign particles ? ?????.
• Pulmonary Lymphatics
• interstitial spaces?? ????
• lymph nodes ? tracheobronchial chain? ????
  airways? ?? ???? ????.
• ?  ? ?? ??? drainage channels? trachea? ????
• left lung?? ?? fluid? ?? the thoracic duct ?
  ?????
• ?? right lung ?? ?? ?? right lymphatic duct ?
  ????.

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Functional respriatory anatomy
1.Rib musles 2.Trachea 3.Circulation 4.innervati
on

•  4.Innervation
• Diaphragm? phrenic nerves (C3-C5 nerve roots) ?
  ??
• unilateral phrenic nere block? ? 25?? pulmonary
  function??
• accessory muscle activity
• intercostal muscle ? ?? ??? thoracic nerve roots?
  ??
• vagus nerves ? tracheobronchial tree? ????? ??
• ????? ?? bronchial smooth muscle ? secretory
  gland ??
• vagal activity bronchoconstriction , bronchial
  secretion
• sympathetic activity (T1-T4) bronchodilation, se
  cretion ??
• nonadrenergic, nonchoinergic bronchodilator
  system? ???
• a- and ß- adrenergic receptors? pulmonary
  vasculature ? ?????  pulmonary vascular tone? ??
  effect ? ???

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 BASIC MECHANISM OF BREATHING

• reoxygenates desaturated blood eliminate CO2
• exchange of alveolar gas ??? ??? small cyclic
  pr. gradient ? ?? ????.
• Spontaneous Ventilation
• spontaneous breathing?? normal pressure
  variation? ????. figure22-3
• Pressure alveoli ? ? gt surrounding
  (intrathoracic) pressure
• pleural pressure ? intrathoracic pressure ?? ?
  ????.  
•        P transpulmonary  Palveolar  -
  Pintrapleural
• Inspiration? chest ? ???? intrapleural pressure?
  -5cmH2O ?? -8 or 9cmH2O? ??    ? ????? alveolar
  pr.??, ??? alveolar-upper airway gradient ??
• expiration?, returns intrapleural pressure to
  -5cmH2O
• elastic recoil of lung reversal of
  alveolar-upper airway gradient ? ????.

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BASIC MECHANISM OF BREATHING

• Mechanical Ventilation
• positive airway pressure ? ????.
• inspiration?,  upper airway? ??? ??? ??? alveoli?
  gas flow ??
• expiratory phase of the ventilator? the
  positive pressure ? ???? ???? gas flow? alveoli
  ??? ???.
• Respiratory Pattern? ?? Anesthesia ? ??
• complex?? postition and anesthetic agents ? ??
  ???.
• supine position?, abdominal breathing predominate
  
• ????? ??? ???? light anesthesia? irregular
  breathing patterns? ????.
• inhalation agent rapid shallow
• nitrous-narcotic slow deep
• Induction? expiratory muscles? ????? expiration
  becomes active

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MECHANICS OF VENTILATION

• lung movement? ?????, respiratory system? ??? ??
  ????.
• Respiratory system? elastic resistance ? the
  gas-liquid ???, ??? nonelastic resistance? ???.
• elastic resistance of tissue ? the gas-liquid ???
  gas flow ? ?? static condition ???? lung
  volume?  ?? ??? pressure? ????.
• elastic resistance? ???? ?(work)? potential
  energy ? ???
• nonelastic resistance to gas flow  air flow ?
  tissue deformation? ?? ?? ??? ????.
• nonelastic resistance? ???? ?? ?? ????.

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MECHANICS OF VENTILATION

• 1.Elastic Resistance
• lung and the chest ? elastic properties? ???.
• chest? expand outward ??? ,?? lung? collapse???
  ??? ??
• recoil properties of the chest deformation?
  ????? ??? ??? ??
• recoil properties of the lung elastin fiber? ??
  ? ??? ?? alveoli?? ?? air-fluid ???? ??????.   
• Surface Tension Forces (????)
• alveoli? ?? ?? gas-fluid ???? ??? bubbles?? ??
• surface tension forces? interface? ??? ???
  alveolar collapse? ????.
• pressure 2 surface tension
•                                radius
• alveolar??   alveolar collapse ??? pressure ?
  surface tension? ???? alveolar size? ?????. (?
  surface tension? ???, alveolar size? ??? ??)
• pulmonary surfactant ? ?? surface tension? ????
  (??? ????) 

? Surfactant? ? ???.
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MECHANICS OF VENTILATION

• Compliance
• compliance?? ??? elastic recoil?? (change in
  volumue divided by change in distending pressure)
  
• supine position chest wall compliance
  ??(abdominal contents? ???)
• lung compliance is defined as
•      CL           change in lung
  volume
•                            change in
  transpulmonary pressure
•       normal 150-200mL/cm H2O
•       lung volume, pulmonary blood volume,
  extravascular lung water, inflammation and
  fibrosis?? ?? ??? ?? ??? ???.
• Chest wall compliance       change in chest
  volume
•                                     
  change in transthoracic pressure
•        normal 200mL/cm H2O
• total compliance (lung and chest wall together)
  100mL/cm H2O
•  1             1          1
• Ctotal            CW            CL

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MECHANICS OF VENTILATION

• 2.Lung Volumes
• ????? ???? important parameter
• lung capacities? ????? ??? measurement? 2?? ? ???
  volume? ???? ????.
• Functional Residual Capacity
• ?? ?? ???? lung volume
• ?? lung? inward elastic recoil ? chest? outward
  elastic recoil? ?????.
• nitrogen wash-out or helium wash ,body
  plethysmography? ??
• FRC ? ????? ??
• Body habitus height? ??, obesity? decrease
• sex ???? 10 ??
• posture supine or prone position? ??
• lung disease lung, chest? compliance? ???? ??,
  restrictive pulmonary disorder?? ??
• diaphragmatic tone 

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MECHANICS OF VENTILATION

• Closing Capacity
• small airway? cartilaginous support? ??, ?? ???
  radial traction? ?? airway? ?? ??.
• lung? basal area?? patency(???)? lung volume? ??
• closing capacity? ?? airway? ?? ??? ?? volume
• tracer gas(Xenon133)?? ??
• ?? FRC?? ??
• posture? ??? ?? ???    
• age? ?? ??
• Vital Capacity
• ?? ?? ? ??? ? ?? ???
• body habitus, respiratory muscle strength and
  chest lung compliance? ??
• normal 60-70mL/Kg

FRCclosing capacity 44?
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MECHANICS OF VENTILATION

• 3. Nonelastic Resistances
• Airway Resistance to Gas Flow
• ???? gas flow? laminar flow? turbulent flow?
  mixture
• laminar flow ?? ?? ??? ?? gas flowing?
  concentric cylinder? ????? ??
•             Flow      Pressure gradient
•                               Raw(airway
  resistance)               
•             Raw     8 Length Gas viscosity
•                             p (Radius)4
• turbulent flow random movement of the gas
  molecule down the air passage
•           Pressure gradient  flow2 Gas
  density
•                                      
  Radius5
• Resistance gas flow? ???? ??. gas density? ??,
  fifth power of the radius? ???(airway caliber?
  ??)
• turbulent or laminar flow ??? Reynold number?
  ????
•    Reynold number linea velocity
  diameter gas density
•                               
   gas viscosity
• laminar flow lt1000   only distal to small
  bronchioles(lt1mm)   
• turbulent flow gt1500   larger airway
• total airway resistance 0.5-2 Cm H2O/L/s
• medium sized bronchi (before 7th generation)? ?
  ?? ???

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MECHANICS OF VENTILATION

• A. Volume-Related Airway Collapse
• at low lung volume (loss of radial traction)
  small airway ? resistance ??? airway resistance?
  ??? lung volume? ???
• B. Flow-Related Airway Collapse
• forced exhalation??, ???? transmural airway
  pressure? ??? airway collapse? ??? ? ?? (dynamic
  airway compression)
• two contributing factors
• generation of a positive pleural pressure
• a large pressure drop across intrathoracic airway
  
• equal pressure point dynamic compression? ????
  airway point? ??
• ????? cartilagenous support? ?? 11th generation
  of bronchioles??
• Emphysema, asthma ??? ??
• C. Forced vital Capacity
• ??? ??? ? ??? ??? ???? ??? airway resistance? ??
  ??? ??? ????.
• FEV1/FVC airway obstruction? ??? ??
• ????? FEV1/FVC gt 80
• FEV1 FVC effort-dependent
• FEF25-75 effort independent, ? ??? ? ??
  obstruction measurement

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MECHANICS OF VENTILATION

• 4.Work of Breathing
• Because expiration is normally passive ,both
  inspiratory expiratory work of breathing is
  performed by the inspiratory muscles (primarily
  diaphragm)
• Ventilation ?? ??? resistance? ???? ??.
• 1. elastic recoil of the chest lung
• 2. frictional resistance to gas flow
• 3. tissue frictional resistance
• respiratory muscle 2-3 of oxygen consumption
  with 10 efficiency
• 90 of  work? ??? ???? (due to elastic airflow
  resistance)
• elastic resistance? ??? ??, ???? ??? tidal
  volume? ????? ??, airflow resistance? ??? ???
  respiratory rate? ????? ??.

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MECHANICS OF VENTILATION

• 5. Effects of Anesthesia on Pulmonary Mechanics
• Effects on Lung Volume Compliance
• induction additional 15-20 reduction in FRC
  (400mL in most patients) - loss of normal
  end-expiratory diaphragmatic tone
• Closing capacity FRC? ?? ?? ???? ????
• Effects on Airway Resistance
• FRC? ??? airway resistance? ???? ??? ???? ??????
  bronchodilating properties? ???? ???
• Effects on the Work of Breathing   
• ?? ? work of breathing? ??? lung chest wall
  compliance? ???? ?? ????.

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VENTILATION/PERFUSION RELATIONSHIPS

• 1.Ventilation
• minute ventilation respirtory rate tidal
  volume (VT)
• alveolar ventilation(VA) respiratory rate (VT
  - VD)
• dead space ( VD) tidal volume (VT) ??? gas
  exchange? ???? ?? ??
• physiologic anatomic dead space    alveolar
  dead space
•   (nonrespiratory
  airway)  (not perfused alveolar)
• ????? 150mL (?? 2mL/kg)
• ???? tidal volume? ? 450mL ???
•      VD         PACO2  - PECO2        33
•      VT               PACO2  
•   ( PACO2 alveolar CO2,  PECO2 mixed expired
  co tension)

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VENTILATION/PERFUSION RELATIONSHIPS

• Distribution of Ventilation
• unevenly distributed
• right  lung  gt  left lung (53 47)
• lower area (dependent)  gt upper area 
  (transpulmonary pr. ? ??)
• upper lung area? alveoli? ?? ? inflated?? ??, ???
  non compliant??
• dependent area? smaller alveoli? more compliant??
  ??? expansion? ? ??
• ?? ??? pulmonary ventilation ??? ??
• ???? ????? ????? ???? ??. ??? ????? ???? ??
  compliance? resistance ???? ?????? alveolar
  filling? ????? ??? ???.
• Time Constants
• lung inflation? ????? ????? ??? ? ??.
•               t total compliance    airway
  resistance
• ???? compliance? ??? ??? alveolar filling? ??? ?
  ??? alveolar filling? asynchrony? ????.

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VENTILATION/PERFUSION RELATIONSHIPS

• 2. Pulmonary Perfusion
• ?? ?? 5L/min? ?? ????, ??? 70-100mL? gas
  exchange? ???? ?? pulmonary capillary? ??.
• capillary volume? ??? ?????? total pulmonary
  blood volume? 500-1000mL  ???? ?? ? ??.
• supine position?? erect ?? 27???? pul. blood
  volume ??
• pul. vascular tone? ?? ?? local factor?
  autonomic sys. ?? ????
• hypoxia? pul. vasoconstriction
• pul. arterial alveolar hypoxia?
  vasoconstriction
• leukotrienes ??, NO ????? ???
• Intrapulmonary shunting? ?? hypoxemia? ????.
• hypercapnia acidosis contstrictor effect
  (hypocapnia?? vasodilate)

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VENTILATION/PERFUSION RELATIONSHIPS

• Distribution of Pulmonary Perfusion
• lower (dependent) portion  gt upper portion
• zone 1 alveolar dead space  ???? PAgtPagt Pv ?
  ???? ???? pul.capill? ??
• zone 2 arterial-alveolar pressure gradient? ??
• zone 3 arterial-venous pressure gradient? ??
• Ventilation/Perfusion Ratios
• alveolar ventilation (VA) 4L/min     pulmonary
  capillary perfusion 5L/min
• ? V/Q rate 0.8 (0 (no ventilation) - ???(no
  perfusion))
• no ventilation
  intrapulmonary shunt
•      0.3  lt  V/Q lt 3.0
• V/Q ratio? ??? ?? ???? O2? resaturated ???.
  CO2? ???? ???? ??

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VENTILATION/PERFUSION RELATIONSHIPS

• 3.Shunts
• shunt ???? ?? mixed venous blood? ????? ?????
  ????? ?? ?? (right to left shunt)
• absolute shunt anatomic shunt V/Q is zero
• relative shunt low but finite V/Q ratio
• Venous Admixture
• pulmonary end-capillary blood? artery?? oxygen
  tension??? ???? ?? ????, pulmonary end-capillary
  blood? ????? ?? mixed venous blood? ?? ???
• venous admixture (Qs)? total cardiac output (QT)?
  ??? ??
•    QS                 CcO2  -  CaO2
•    QT                   CcO2  -  CvO2
• CcO2 ???? pulmonary end-capillary bl.? oxygen
  content
• CaO2 arterial oxygen content
• CvO2 mixed venous content
• ?? Qs/ QT?  deep bronchial vein? pulmonary vein,
  thebesian circulation, ??? ??? V/Q ??
  communication? ?? ??
• ???? venous admixture? 5????.

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VENTILATION/PERFUSION RELATIONSHIPS

• 4.Effects of Anesthesia on Gas Exchange
• ??? ?????, hypoventilation, intrapulmonary shunt?
  ?????, V/Q ratio? ??? ?????.
• ??? ??? ?? ??? atelectasis? airway collapse? ??
  ?? ?? ? ?? venous admixture? 5-10????.
• NO? ??? inhalation agents? high dose?? hypoxic
  pulm.vasoconstriction? ????. ? ??, O2 tension?
  3040 ?? hypoxemia ? ????, PEEP? venous
  admixture? ?????? ?????.
• ??? high inspired oxygen concentration(gt50)? ???
  absolute shunt? ???? ? ??.
• ? ???? ??? low V/Q ratio? ?? alveoli?? ? ?? ??
  ??? ? ????? ??, complete collapse? ???? ???
  ????.(absorption atelectasis)

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ALVEOLAR, ATERIAL VENOUS GAS TENSIONS

•  gas mixture each gas pressure? concentration?
  ??
•     PIO2 PB FiO2 (159.6mmHg760mmHg0.21)
• PB barometric pr. 
• FiO2 inspirarted oxygen? ??
• ??   7? mmHg? ??? ? ??
• kilopascal? ??? ?? ??
• 1. Oxygen
• Alveolar Oxygen Tension
• ?? ? inspired gas? humidification ?? inspired
  tension of oxygen? water vapor?? ??
•            PIO2 (PB -PH2O) FiO2
• alveoli?? ??? gas? ??? alveolar gas(O2, CO2)?
  ????. ???
•            PAO2 PIO2 -PaCO2/RQ
• PaCO2 arterial CO2 tension, RQ respiratory
  quotient
• PaCO2? ??? ??(75mmHg??)? room air(PaO2?
  60mmHg??)?? hypoxia? ?? (but high inspired oxygen
  concentration?? ??)
• inspired oxygen concentration() 6 PAO2 mmHg

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ALVEOLAR, ATERIAL VENOUS GAS TENSIONS

• Pulmonary End-Capillary Oxygen Tension (PcO2)
• ???? ???? ?? PcO2 PAO2
• PcO2 (pul.end-capil.O2 tension)
  alveolar-capillary membrane ??? oxygen diffusion
  rate? pulmonary capillary blood volume transit
  time? ?? ??
•      capillary transit time pulmonary capillary
  blood volume
•                                      
  cardiac output
•                                70mL / 
  5000mL/min   (0.8sec)
• Oxygen? hemoglobin? ?? ?? alveolar gas??? blood?
  ?? ????? rate-limiting factor? ??
• pulmonary diffusing capacity? alveolar-capillary
  membrane? capacity? permeability ?? ???,
  pulmonary blood flow? ??                
• alveolar-capillary membrane?? ?? ??? oxygen
  diffusing capacity(DLO2)? ??
•           DLO2      oxygen uptake
•                         PAO2 PcO2
• PcO2? ??? ??? ? ?? DLCO? ?? ??
•           DLCO       carbon monoxide uptake
•                              PACO  -PcCO
• DLCO? ??? alveolar capillary memb.? ?? gas
  transfer? ??? ??
• due to abnormal V/Q ratio, destruction of
  alveolar-capillary membrane, short capillary
  transit time

29
ALVEOLAR, ATERIAL VENOUS GAS TENSIONS
O2??? Useful

• Arterial Oxygen Tension
• PaO2? PAO2?? ??? ? ??
• alveolar-arterial oxygen partial gradient?
  15mmHg????
• ??? ?? ?? 20-30mmHg? ??   
• PaO2      102 -age/3  
• noraml range 60-110mmHg(8-13kPa)
• ??? FRC? ?? ???? closing capacity? ??? ??? ??   
• hypoxemia? ?? ?? ??? alveolar-arterial
  gradient??? ??
• A-a gradient ? right to left shunt, V/Q scatter?
  ??, mixed venous oxygen tension?? ?? ??
• A-a gradient? shunt? ?? ???? mixed venous
  tension? ???
• A-a gradient? ?? cardiac output? ??? mixed venous
  oxygen tension? ?? 2? ???? ??? cardiac output?
  intrapulmonary shunt?? ??? ???? ????
• oxygen ??? hemoglobin ??? ?? mixed venous oxygen
  tension? ?? ??? ??? PaO2? ??? ??? (high oxygen
  consumption low hemoglobin concentration? A-a
  gradient? ?????, PaO2? ?????)

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ALVEOLAR, ATERIAL VENOUS GAS TENSIONS

• Mixed Venous Oxygen Tension
• normal 40mmHg
• ?? oxygen consumption oxygen delivery? ???
  ??? ????.
• pul. artery catheter? ?? ? ? ??.
• Mixed venous oxygen tension(PvO2)? alterations

31
ALVEOLAR, ATERIAL VENOUS GAS TENSIONS

• 2.Carbon Dioxide
• mitochondria??? aerobic metabolism? ???
• Mixed Venous Carbon Dioxide Tension
• normal 46mmHg
• ??? ???? ?? ??????? blood? ??? ??
• Alveolar Carbon Dioxide Tension
• alveolar CO2 tension(PACO2)? total CO2 ???
  alveolar ventilation(CO2??)?? balance? ????.
•                PACO2     VCO2
•                               VA
• PACO2? CO2???? CO2??? ? ???
• ?, CO2 ???? ?? ?? ???? ??, CO2? ??, ????? ? ? ??
  ??? ?? ??? PACO2? alveolar ventilation? ? ??
• Pulmonary End-Capillary Carbon Dioxide Tension
• PcCO2 PACO2
• alveolar-capillary membrane? ?? CO2 diffusion
  rate? ??? 2???
• Arterial Carbon Dioxide Tension
• normal PaCO2? 38 /- 4mmmHg ( 5.1 0.5KPa)
• ???? arterial to alveolar gradient? ??? V/Q
  abnormality ??? ??? 
• End-Tidal Carbon Dioxide Tension
• end-tidal CO2 tension? ????? PaCO2? ?? ?? ??

32
TRANSPORT OF RESPIRATORY GASES IN BLOOD

• 1.Oxygen
• 2 form?? ?? solution? ?? ???, hemoglobin? ?????
  association?
• Dissolved Oxygen
• ?? ???? ?? ???? ??? Herney's law? ?? ?? ? ??. 
•          Gas concentration    a partial
  pressure
•                a ??? ??? ??? ????? gas ?? ??
• ?? ????? ?? 0.003mL/dL/mmHg
• Hemoglobin
• 4?? heme? 4?? protein subunit?? ??? complex large
  molecule
• Heme oxygen-binding site? essential part? iron
  porphyrin compound
• ?? hemoglobin molecule (hemoglobin A1)
• 2?? a- 2?? ß-chain?? ??
• 4?? subunit? amino acid residue?? weak bond? ??
• hemoglobin 1g? 1.39mL? ??? ?? ? ??.

33
TRANSPORT OF RESPIRATORY GASES IN BLOOD

• Hemoglobin Dissociation Curve
• ? hemoglobin ? 4?? ????? ???
• hemoglobin saturation? ?? ??? ??? total oxygen
  binding capacity? ?? percent? ??
• ? 3???? binding? ??? binding? ??? ??
• ??? ??? oxygen receptor? ???? curve? flatten ??
  ??.

34
TRANSPORT OF RESPIRATORY GASES IN BLOOD
Alkalosis Hypothermia 2,3-DPG??

• Factors influencing the Hemoglobin Dissociation
  Curve
• oxygen binding? ??? ????? ??? factor
• hydrogen ion concentration, CO2 tension,
  temperature,
• 2,3-diphosphoglyceride (2,3-DPG)concentration
• P50 hemoglobin? 50? ???? oxygen tension
• shift to right (increasing P50)
• make more oxygen available to tissue
• shift to left (decreasing P50)
• oxygen affinity ??, reducing availablity to
  tissue
• normal P50 26.6mmHg(3.4kPa)
• ??? ??? Bohr effect? ?? hemoglobin? ???? ??? ???
• CO2 tension physiologically important
• CO2 tension? ???? ?? 2???? ????? ????.
• 2,3 DPG glycolysis? ???? anaerobic metabolism??
  ??
• chronic anemia ???? ??? ????? ??
• blood transfusion? oxygen-carrying capacity? ???
  ???.

Acidosis Hyperthermia 2,3-DPG??
P50
Affinity? ?? O2 release to tissue O2 uptake? ??
??.
26.6mmHg
35
TRANSPORT OF RESPIRATORY GASES IN BLOOD

• Abnormal Ligands Abnormal Forms of Hemoglobins
• carbon monoxide, cyanide, nitric acid, ammonia ??
  hemoglobin? ?? ?? ? ?? (shift to left)
• ?carbon monoxide 200-300? ??
• ?carboxyhemoglobin? ??
• methemoglobin heme? ?? iron? trivalent form??
  ??(?? ?? ??)
• methylene blue or ascorbic acid? methemoglobin??
  Hb??? ??? ????.
• abnormal hemoglobin protein subunit
  composition? variation? ?? ??
• fetal hemoglobin, hemoglobin A2. sick hemoglobin
• Oxygen Content
• total O2 content solution? ?? ?? hemoglobin? ??
  ???? ?? ?
• oxygen content (0.003mL O2/dL blood/mmHg) PO2
  
•                          
  (SO2 Hb 1.31mL/dL blood)
• CaO2 19.5mL/dL blood     CvO2 14.8mL/dL blood
  
• ???, arteriovenous difference? ?? ? ??.
• CaO2 -CvO2 4.7mL/dL

36
TRANSPORT OF RESPIRATORY GASES IN BLOOD

• Oxygen Transport
• respiratory circulatory function? ?? ??
• Total oxygen delivery to tissue(DO2) arterial
  oxygen content cardiac output (QT)
• DO2 20mL O2/dL blood 50dLper blood/min
•           1000mL O2/min 
• Frick equation? ?? ??, ?? ?, ? ??? ?? ??? ????
•         oxygen consumption   VO2   QT (CaO2 -
  CvO2)
•                   CaO2    VO2        CvO2
•                               QT
• extraction fraction (CaO2- CvO2)/ CaO2 5/20
  25
• ??? hemoglobin? ??? ?? ? 25? ??, ???? ??? 25??,
  ??? 25??? ??
• delivery?? ?? ?????? ?? consumption? ??
  (extraction? ?? ??)

37
TRANSPORT OF RESPIRATORY GASES IN BLOOD

• Oxygen Store
• ???? ?? ?? ???? 1500ml
• 1. oxygen remaining in the lung (FRC) important
  store (80?? ????)
• 2. hemoglobin? ?? ?? ?   ???    
• 3. dissoluted in body-fluid       ???
• ?? ?? oxygen content FiO2 FRC
• FiO2 0.21       FRC  2300mL  ? 90? ? severe
  hypoxemia ??. (O2 content480ml)
• FiO2 1          FRC  2300mL    ?  4-5? ?
  ????
• ??? ??? induction? preoxygenation? ??? ??.

38
TRANSPORT OF RESPIRATORY GASES IN BLOOD

• 2.Carbon Dioxide
• transfort 3 form
•     1.dissolved in solution,  2. bicarbonate 
•     3.carbamino compound??? protein
• Dissolved Carbon Dioxide
• ???? ? ???   0.067mL/dL/mmHg
• Bicarbonate
• ?? ?? carbonic acid? bicarbonate? ??
•       H2O    CO2  ?  H2CO2  ?  H    HCO3-
• on the venous side of systemic capillary
• ???? carbonic anhydrase ? ??? CO2? ???? ???,
  ????? bicarbonate? ?? plasma? ?????
• chloride? ??? balance? ?? plasma?? ???? ????
• in pulmonary capillary
• chloride ion? ???? ?? ???, ???? bicarbonate ion?
  ??? CO2? ???? alveoli?? ????
• ?? Chloride or Hamburger shift ?? ??.
• Carbamino Compounds
•     R-NH2    CO2  ?  RNH-CO2-    H
• carbamino-hemoglobin? ??? CO2? ??
• deoxygenated hemoglobin? oxygenated hemoglobin?
  ?? 3.5??? CO2? ? ??

39
TRANSPORT OF RESPIRATORY GASES IN BLOOD

• Effects of Hemoglobin Buffering on Carbon Dioxide
  Transport
• hemoglobin? physiologic PH??? histidine? ???
  buffer? ??
• Hb? oxygenated state? ?? ???? ????.
• tissue capillary?? ???? ?? O2? ???
• CO2   H2O    HbO2 ? HbH    HCO3-    O2
• Lung?? ??? ?? oxygenation ???
• O2    HCO3-    HbH  ?  H2O    CO2    HbO2
• Carbon Dioxide Dissociation Curve
• Carbon Dioxide Stores
• ?? 120L in adult
• ?? dissolved CO2? bicarbonate ???
• ??? ?? ?? imbalance?, 20-30? ??? ??? ???
  equilibrium? ?? 

40
CONTROL OF BREATHING

• brain stem ? respiratory center??? rhythmic
  neural activity? ??
• 1.Central Respiratory Center
• Medulla?? ????, two medullary group of neuron ?
  ??.
• 1.dorsal respiratory group inspiration??? ???
• 2.ventral respiratory group expiration??, ???
• basic rhythm
• dorsal group??? intrinsic, spontaneous discharge
  activity ?? dorsal ventral group??
  reciprocating activity? ??
• two pontine area? dorsal medulla? ??? ??
• ??? respiratory rate rhythm
• 1. lower pontine (apneustic) center  excitory
• 2. upper pontine (pneumotaxic) center 
  inhibitory

41
CONTROL OF BREATHING

• 2.Central Sensor (Chemoreceptor)
• anterolateral surface of medulla
• respond to CSF (H)? ??
• effective in regulating PaCO2
• (BBB is permeable to dissolved CO2)
• PaCO2? ??? CSF H? ???? chemoreceptor? ??? ???,
  adjacent respiratory medullary center? ???
  alveolar ventilation? ??????? PaCO2? ???
• ?? very high arterial PaCO2? ventilatory
  response? ???? CO2 narcosis?? ?
• ventilation? zero? PaCO2 (apneic threshold) ??
  ? ?? ?? ?? PaCO2 ? apneic thershold ??? ????.
• pph. chemoreceptor?? ????? central chemoreceptor?
  hypoxia? ?? ????.

42
CONTROL OF BREATHING
Pph. chemoRc Lung receptors

• 3.Peripheral Sensor
• Peripheral Chemoreceptors
• 1. carotid bodies (at the bifurcation of the
  common carotid arteries)
• principal peripheral chemoreceptor in human
• PaO2, PaCO2, PH, arterial perfusion pressure? ???
  ??
• glossopharyngeal nerve ? ?? central respiratory
  centers ? ??????.
• cyanide, doxapram, large dose of nicotine?? ???
• PaO2? ???? 50mmHg??? ???? ??? ????? ???.
• cell of the carotid body (glomus cell)
  dopaminergic neuron
• cf) antidopaminergic drug, bilateral carotid
  surgery
• ? hypoxia? ??  pph. ventilatory response? ????
• 2. aortic bodies (surrounding the aortic arch)

43
CONTROL OF BREATHING
Pph. chemoRc Lung Receptor

• Lung Receptors
• carried centrally by vagus nerve
• stretch receptor smooth muscle of airway? ??
• lung? ??? inflate? inspiration ?? (Herning-Breuer
  inflataion reflex)
• lung? deflate? exhalation? ?? ?(deflation reflex)
  
• human? ?? minor role
• irritant receptor( in tracheobronchial mucosa)
• J (juxtacapillary) receptors (interstitial space
  within alveolar wall) interstitial space vol.
  ?? ?? ?? ????? ???? dypnea? ???
• Other receptors
• various muscle joint receptor on respiratory
  muscle the chest wall (important during
  exercise pathologic condition associated with
  decreased lung or chest complians)

44
CONTROL OF BREATHING

• 4.Effects of Anestheisa on the Control of
  Breathing
• Hypoventilation? ???.
• dual mechanism
• central depression of the chemoreceptor
• depression of external intercostal muscle
  activity
• hypoventilation? ??? ????? ?? 
• hypoxemia? ?? pph. response? central CO2
  response?? ????? sensitive

45
NON-RESPIRATORY FUNCTIONS OF THE LUNG

• Filtration Reservoir Function
• filtration
• acts a filter for debris
• facilitates breakdown entrapped fibrin debris
• reservoir function
• Metabolism
• 1.pneumocyte? surfactant?? ? ???, extrahepatic
  mixed-function oxidation? major portion? ??
• 2.neutrophil macrophage oxygen derived free
  radical
• 3.pulmonary endothelium metabolize a variety of
  vasoactive compound
• 4.angiotension?? angiotensin?? ??(surface of the
  pul. endotheium)